Tool for slitting the sheaths of encased wires



March 10, 1942. o. M. RYBOLT 2,275,867

TOOL FOR SLITTING SHEATHS OF ENCASED WIRES Filed March 29, 1959 IN VENTOR.

Ora M Rvba/f v M 272$? ATTORNEY.

Patented Mar. 10, 1942 OFFICE TOOL FOR SLITTING THE SHEATHS F ENCASED WIRES Ora M. Rybolt, Darts, Mich., assignor to Magnetic Tool Company, Detroit, Mich.

Application March 29, 1939, Serial No. 265,914

, 2 Claims. (01. 3041) This invention relates to tools for slitting non-metallic sheathing from electric wiring and the like.

The principal object of the inventionis to provide an inexpensive and efficient device adapted to slit the outer sheathing of wires or cables containing more than a single wire or several sheathed wires and that is adaptable for slitting of various sizes of sheathed wires or cables.

A feature of the invention resides in the provision of a device capable of taking a certain maximum size and automatically adjustable for slitting varying sizes from a minimum to a maximum for which the tool may be adapted and it is also an object of the invention to provide for an adjustment of the depth tcwhich the slitting knife enters the casing of the wire whereby the casing only may be severed without danger of cutting the wires or'the additional sheathing in surface contact therewith.

Another feature and object of the. invention is to provide a wire slitting device of a tubular form through which the wire may pass. in the slitting operation and preventing the hands of the operator coming in frictional contact with the sheathing.

These and other objects and novel features of the invention are hereinafterv more'fully described and claimed, and the preferred form of device for slitting the casing of encased wires is shown in the accompanying drawing 'in which- Fig. 1 is a plan view showing my improved wire slitter.

Fig. 2 is an elevation thereof partly in section. 1:

Fig. 3 is an elevation showing the device in position for slitting a casing of a wire.

Fig. 4 is a portion of a sheathed wire showing a slitted end of the casing.

Fig. 5 is an enlarged section taken on line 5-5 of Fig. 2.

The invention is adapted for use in slitting the casing of various types of wires having a fabric like sheathing in which there is sometimes single wires enclosed in the sheathing or a plurality of wires or in which two or more sheathed electrical conductors are secured in an additional common sheathing, the slitter being automati cally adjustable for slitting the sheathing of wires of various sizes.

The device as shown in Fig. 1 is preferably formed of a sheet metal body I rolled to an oval form in cross section as indicated in Fig. 6 and is open ended to permit the ready insertion of tion I is at the right hand side as shown in Figs. 1, 2 and 3 and the forward or entrance end for the wire is at the left hand side.

At the forward end, the body is cut out as shown at 2 providing an integral forwardly projecting and rigid portion 2a and a tapered wire clasping portion, indicated at 3, is secured to one side of the body I at the forward end by means of a spring element 4 secured at one end to the body by the screws 5 and also secured to the rear end of the member 3 as by screws 6. The wire clasping portion 3 is similar in form and is positioned in a parallel opposed relation to said projecting portion 2a. This spring member 4 is pre-shaped to normally hold the member 3 in its open position to permit the ready introduction of a wire into the end of the slitter. The spring member 4 extends forwardlyiof the screws 6 and is provided at the forward end with an adjusting screw 1 which passes through a reinforced end of the spring member 4 which may be an integral return bent portion as indicated at. 8. This reinforced end is apertured and threaded to receive the screw 1 and the screw engages the upper face of the hinged wire clasping member 3. The spring element is of such width at the forward end as to provide stock permitting a portion ,9 to be struck out from the body of the metal of a triangular form and sharpened to provide a knife edge ill. The screw 1, it will be noted, permits adjustment of the extent towhich the knife edge projects through an aperture II in the hinged member 3 and thus limits the extent to which the knife may be introduced into a sheathed wire l2. In introducing the wire into the end of the member substantially as shown in Figs. 1, 2 and 3, the hinged member 3 is in its normal uppermost position and under the control of the thumb of the operator who grasps the body of the device in his hand and after the sheathed wire is in-. troduced thereinto the operator moves the element 3 downwardly to the position shown in Figs. 3 and 5 causing the knife edge to penetrate the sheathing to a predetermined depth.

The operator, by subsequently drawing the wire in the direction of the arrow at the left of Fig. 3 and the instrument in the direction of the arrow shown at the right of Fig. 3, slitsthe sheathing and the length of the slit will be determined by te extent to which the wire is introduced into the device. In fact the wire may be slitted for full length if desired by passing the instrument longitudinally thereacross under the condition and a wire therein or therethrough. The body porrelationship of the parts as shown in Fig. 3.

In Fig. 4, I have shown the end of the wire slitted with the outer covering [3 outturned exposing the inner sheathing 14 which it is not desired to slit. In fact the inner sheathing is usually formed of a spiral wrapping paper or other convenient sheet type of strip and the adjustment of the extent to which the blade 9 extends into the sheathing is thus important to avoid cutting the inner sheathing or coming in contact with or disarranging the wires of which there are usually a multiplicity.

In the section Fig. 5, the knife edge is shown as cutting practically through the outer sheathing and in this view the wire is shown as of comparatively small size and it is possible to use -awire of such size that the upper surface is practically in contact with the inner surface of the hinged member 3. With such a wire, the forward end l5 of the hinge member will practically ride the surface of the wire being slitted and to have a proper depth of cut the screw may under such condition be adjusted to increase or decrease the extent to which it cuts into the sheath.

Preferably the spring 4, which naturally tends to hold the element 3 in an open position is also extended to receive a screw member which places the forward end of the spring member under tension. The structure may be otherwise made, however, if desired but a desirable feature is to provide a member 3 that is normally and automatically sustained in an open position requiring the pressure of the thumb of the operator to place the same in a slitting position in respect to the sheathed wire.

From the foregoing description, it will be understood that the device is of very simple construction and is highly efficient in operation and may be made in various sizes for use with wires much larger than would be appropriate for the device in the scale shown by the drawing and while I have shown the body element as being oval in form particularly to take a double strand of sheathed wires in a common casing, it may be of other forms if desired. It is therefore evident that various changes may be made in the structure without departing from the spirit and scope of the invention as set forth in the appended claims.

Having thus briefly described my invention, its

utility and mode of operation, what I claim and desire to secure by Letters Patent 0f the United States isl. A tool for slitting the casing of a sheathed Wire, comprising a tubular body providing a hand hold through which the wire may be passed from end to end, the said body having an integral half tubular portion projecting forwardly of the forward end of the body and providing a support for one side of the wire introduced into the body, a wire clasping member of half tubular form in cross section hinged to the end of the body opposite the base of said half tubular portion and manually movable to engage the surface of the wire opposite that supported by the integral half tubular body portion, said wire clasping member having a cutter projecting toward said half tubular portion, and spring means tending to move said wire clasping member in a direction away from the half tubular portion subsequent to a slitting operation to permit movement of the tool along the wire for a subsequent slitting operation. 2. A tool for slitting the casing of a sheathed wire comprising a body providing a handheld and having a longitudinal aperture through which the wire may be passed, a member projecting forwardly of the forward end of the body and shaped to engage about a wire on one side thereof, a member substantially complemental thereto adapted to engage about the other side of the wire, a spring secured to the body and to the said movable member normally tensioned to move the said complemental member away from the wire, said spring extending to the forward end of the movable member, said movable member having an aperture, a cutter carried by the spring member near its forward end and projecting through the aperture, and an adjusting screw extending through the end of the spring to engagement with the said movable member whereby, through rotation of the screw the distance to which the cutter extends through the aperture may be varied, said movable member being adapted to be moved by pressure applied thereto by the thumb of the operator to engagement with the wire surface and forcing the cutter into the casing to an extent determined by the said adjustment of the cutter, the parts when in the cutting relationship being adapted to be moved longitudinally of the wire to thereby slit the casing.

ORA M. RYBOLT. 

